Ram operated aircraft heater with ram anti-icing means



June 15, 1948. H. J. DE N. MccoLLuM 2,443,262

RAH OPERATED AIRCRAFT HEATER WITH RAM ANTI-ICING MEANS Original FiledJan. 15, 1943 Patented June 15, 1948 RAM OPERATED AIRCRAFT HEATER WITH 4RAM ANTI-ICING MEANS Henry J. De N. McCollum, deceased, late of Chi-.cago,.Ill., by Thelma McCollum, executrix, Chi.

cago,- Ill.',

assignor to Stewart-Warner Corporation, Chicago, Ill., a corporation ofVirginia Original application Janu I 472,458. Divided and thisapplication Novem- 7 bet 5, 1945, Serial No. 626,685

2 Claims.

The present invention relates to aircraft heaters and more particularlyto aircraft heaters of the combustion type which receive air forcombustion and for ventilation by means of a scoop or ram located in theair stream outside the aircraft. Such rams frequently take the form ofan open ended tube or its equivalent which projects through the sidewall of the airplane and has its open end facing in a forward direction.Rams also sometimes comprise an opening in the leading edge of theairplane wing. In either case, the dynamic effect of the airplane movingthrough the air at high speed creates a static pressure within the ramand connected duct work which causes a flow of air through the heaterand to the space to be heated. Sometimes the space to be heatedcomprises the cabin of the aircraft while in other heating systems thehot ventilating air is distributed into a double skin arrangement overthe leading edge of the wings or tail surfaces to raise the surfacetemperature sufliciently above the freezing point, so that ice cannotform thereon.

The principal object of the present invention is to provide a novelheating system of the above type which cannot be rendered inoperative byicing conditions in the vicinity of the aircraft.

Other objects and advantanges will become apparent from the-followingdescription of a preferred embodiment of .nyinvention whichis.

illustrated in the accompanying drawing wherein a single figure'diagrammatically illustrates an arrangement embodying features of theinvention.

The numeral l indicates the side wall or skin surface of an aircraftwing or fuselage within which a combustion heater I2 is located. Thisheater may be of the type more fully illustrated and described in thecopending application of Henry J. De N. McCollum bearing Serial No.

172,458 and filed January 15, 1943, now Patent No. 2,427,221 issuedSept, 9, 1947, for Aircraft heating apparatus, of whichthis applicationis a division. Application Serial No. 472,458 is in part a continuationof a previously filed and now abandoned application of Henry J. De N.McCollum bearingserial No. 373,751 filed January 9, 1941, for aninvention entitled "Heating apparatus.

The heater l2 comprises an outer shell or casing l4 through whichventilating air can flow. Within the casing the heater is provided atone end with a burner IS in which a combustible mixture of liquid fueland air' is burned, such that the hot products of combustion empty intoary 15, 1943; Serial Nd;

a heat exchanger portion l8 also located within the shell l2. Thusventilating air flowing through the casing l4 removesheat from the heatexchanger [8 with the result that the ventilating air issuing from thedownstream end of the heater is considerably elevated in temperature.

The heater I 8 is supplied with ventilating air by means of ascoop orram which comprises an open mouthed tube with the opening facing in thedirection of flight. This tube extends generally backwardly and thenceinwardly where it is connected with a duct 22 leading to the inlet endof the heater. The downstream end of the heater is similarily connectedto a duct 24 which conveys the hot air to the space to be heated.

A combustible mixture is supplied to the burner is by a combustion airpipe 26 which opens into the duct 22 upstream of the heater and whichhas its opposite end connected to a balanced carburetor 28 connected toa source of liquid fuel, for instance, the ordinary engine fuel, by wayof a pipe 30. the combustion air 'is mixed with the liquid fuel to forma combustible mixture which is supplied to the burner I6 by way of amixture tube 32.

Although in the interest of clarity of illustration no means is shownforigniting the combustible mixture in the burner.l6, such details ofheater construction can be learned by consulting the previously referredto ,copending application, .SerialNo. 47 5 and the patents and otherapplications referred to in that application. The

hot products of combustion pass from the burner l8 into the previouslyreferred to heat exchanger l8 and ultimately are returned to the airstream by way of an exhaust pipe 34 which projects through the wall IUof the airplane and opens rearwardly of the aircraft.

The ram 20 is provided with a sheet metal jacket 36 which is weldedaround the open end of the ram 20 and which extends generally rearwardlyaround the ram tube in spaced relation thereto and has its rearward endopen as at 38 within the interior of the aircraft. The forward portionof this jacket is connected to a hot air tube 40 which extends inwardlythrough the skin and thence generally parallel to the heater and at itsrearward end extends into the duct 24 so as to form a ram 42 to receivehot ventilating air.

When the heater is in operation, ventilating air flows inwardly at the'scoop as indicated by the arrows, flows rearwardly to the heater casingI4 at its inlet end. The air then passes through the heater where itstemperature is raised by the heat exchanger l8. Ultimately it reachesthe Within the carburetor 28 space to be heated through the duct 24. Aportion of this hot air is diverted by means o! the connection 42 andilowsthrough the hot air tube -,40 to the space within the jacket 36.This heats the jacket 38 and also serves to heat the ram 20 so as toraise the temperature 01' their surfaces above the icing point under allconditions of operation. 7

The temperature of the air leaving the jacket 36 is considerably reducedsince it loses heat to the ram 20 and Jacket 86. Asa rule, however, itis still sufliciently warm to be useful for heating purposes andthereforeit is brought back into the aircraft and discharged at theopening 38. It preferred, however, the open end can be located outsidethe aircraft wall It], so that the air after heating the scoop andjacket 66 exhausts dircctly to the atmosphere. i

Having described the invention, what is claimed as new and useful anddesired to be secured by Letters Patent 01 the United States is:

1. Inan airplane, a heating system having means forming a combustionchamber and a heat exchanger, means including an opening to theatmosphere directed forwardly o1 the airplane to supply combustion airto said chamber and to supply ventilating air to said heat exchanger, ajacket around and forming an air passage adiacent a portion of saidmeans, ventilating air duct means connected to the outlet of said heatexchanger for conveying heated air therefrom to a space to be heated,and means diverting to said jacket a portion of the heated air flowingthrough said duct.

2. In an airplane, a heating system having means forming a combustionchamber and a heat exchanger connected to receive products of combustiontherefrom, means including an. openin to the atmosphere directedforwardly of the airplane to supply combustion air to said chamber andto supply ventilating air to said heat exchanger, a jacket around andforming an 'air passage adjacent a portion or said means, ventilatingair duct means connected to the outlet oi said heat exchanger forconveying a portion of the heated air therefrom to a space to be heated,and conduit means including said Jacketior conveying another portion ofthe heated air flowing through said duct to the space to be heated.

THELMA MoCOLLUM, Executria' of the Last Will and Testament of Henry J.De N. McCollum, Deceased.

REFERENCES crrEn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 286,341 Spear Oct. 9, 1883 StrongNov. 24, 1925 Certificate of Correction Patent N 0. 2,443,262. June 15,1948.

HENRY J. DE N. MCOOLLUM, DECEASED, BY THELMA MCCOLLUM, EXECUTRIX It ishereby certified that error appears in the above numbered patentrequiring correction as follows: I the drawing, duct 22 should e shownconnected to the Signed and sealed this 19th day of October, A. D. 1948.

THOMAS F. MURPHY,

Assistant Oommz'ssz'oner of Patents.

